Tobacco smoke filter

Abstract

Tobacco smoke filters having a composite substantially cylindrical inner member formed from two semi-cylindrical inner elements and overwrapped with a common plug wrap. The composite inner member has a discrete inner cavity formed in each semi-cylindrical element and a composite cavity formed by a depressed portion in each semi-cylindrical element. A substantially smooth outer surface is provided on the composite inner member for attaching a conventional plug wrap without the need for an internal glue line. Separate cylindrical elements are reformed into semi-cylindrical elements and crimped to provide depressed pockets, following which the semi-cylindrical elements are mated and overwrapped to produce the final product.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A smoke filter means including a filter element comprising: a. an axially elongated, hollow, outer member;   b. a pair of mating, axially, elongated, hollow, inner elements together forming a substantially cylindrical composite inner member;   c. said outer member including an inner surface and having spaced end portions;   d. said inner elements comprising a filtering material and including an inner surface and an outer surface and having spaced end portions;   e. said inner and outer surfaces of each inner element including a semi-cylindrical portion, said semi-cylindrical portion of said outer surfaces of said inner elements together forming a substantially cylindrical outer surface of said composite inner member;   f. at least the major portions of said outer surface of said composite inner member being juxtaposed to said inner surface of said outer member throughout their lengths to continuously support said outer member and to at least substantially preclude axial passage of smoke across the area therebetween;   g. said inner and outer surfaces of each inner element also including connecting portions extending across each inner element between said semi-cylindrical portions of said inner and outer surfaces of said inner elements, said connecting portions facing each other in said composite inner member;   h. substantially flat portions of said connecting portions of said outer surface of each inner element extending diametrically across said inner element, said flat portions of said inner elements being juxtaposed in said composite inner member to at least substantially preclude axial passage of smoke across the area therebetween;   i. depressed portions of said connecting portions of said inner surface of each inner element axially spaced from said flat portions of said outer surface of said inner element being juxtaposed to said semi-cylindrical portion of said inner surface of said inner element to at least substantially preclude axial passage of smoke across the area therebetween;   j. whereby each inner element includes a discrete inner cavity defined by its inner surface and a second axially spaced cavity defined by said depressed portion of its outer surface, said second cavities of said inner elements being juxtaposed in said composite inner member to define a composite second cavity, said discrete first cavities and said composite second cavity being separated by said filtering material of said inner elements so that smoke passing through said filter element must travel through one of said discrete first cavities, said filtering material and said composite second cavity.   
     
     
       2. A cigarette comprising, in combination, a tobacco rod and a filter means secured in end-to-end relationship to one end of said tobacco rod, said filter means including a filter element as defined in claim 1. 
     
     
       3. A filter rod comprising a multiplicity of filter elements as defined in claim 1 integrally connected together with said discrete first cavities of said inner member of alternating filter elements in said rod juxtaposed to each other and said commposite second cavity of said inner members of alternating filter elements in said rod juxtaposed to each other. 
     
     
       4. A filter element according to claim 1 wherein said filtering material comprises cellulose acetate tow. 
     
     
       5. A filter element according to claim 1 wherein at least one of said cavities is at least partially filled with a further smoke-modifying material. 
     
     
       6. A filter element according to claim 5 wherein said further smoke-modifying material comprises activated carbon.